This application relates to a scroll compressor having injection tubes to inject a fluid into compression ports, and through a top shell.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a first scroll member has a base and a generally spiral wrap extending from the base. A second scroll member has a base and a generally spiral wrap extending from its base. The wraps of the two scroll members interfit to define compression chambers. The second scroll member is caused to orbit relative to the first scroll member, and as the two orbit the size of the compression chambers decreases and trapped refrigerant is compressed.
There are many enhancements for refrigerant cycles, such as those incorporating scroll compressors. One enhancement is the use of an economizer cycle. In an economizer cycle, refrigerant compressed by the compressor is delivered downstream to a condenser. Downstream to the condenser a portion of the refrigerant is tapped and expanded. This expanded tapped refrigerant is passed in heat exchange relationship with a main refrigerant flow in an economizer heat exchanger. This sub-cools the main refrigerant flow, and provides additional capacity at a downstream evaporator. The expanded tapped refrigerant downstream of the economizer heat exchanger is passed back into the scroll compressor through economizer injection ports. Typically, this occurs at an intermediate compression point.
In the prior art, the injection of economizer fluid, or other liquid, has occurred through a sidewall of the shell for the compressor, and into the base of the first scroll member. Complex passages, cover plates, etc., have been required. It would be desirable to simplify the provision of economizer injection into a scroll compressor.
In one known scroll compressor, the economizer injection ports extend through the top of the scroll compressor. However, in this proposed scroll compressor the first scroll member is of a type that may move axially. Thus, the first scroll member is not fixed to the economizer injection tubes, but rather slides along the tubes.